290 
NEWTS AND SALAMANDERS. 
newts are very abundant in the western portion of this region, but as we 
proceed eastwards they become less numerous, and we notice an approximation to 
American types of the order, although only two genera are common to the Old and 
New Worlds. North America is especially rich in Tailed Batrachians, containing 
more than half the representatives of the entire suborder, and having the two- 
legged salamanders ( Sirenidce ) peculiar to it. Axolotls are here especially abundant, 
and there are also peculiar genera belonging to the families of the fish-like and 
gilled salamanders. The Oriental region possesses only two species, namely, a 
peculiar genus ( Tylotriton ) of newts in Yunan and the Eastern Himalaya, and 
an axolotl in Siam. Tropical America, on the other hand, has ten species; 
among which may be specially noticed the newts of the genus Spelerpes, 
which are also represented by one species from Central America and the West 
Indies, and two others from the mountains of Colombia, Ecuador, and Northern 
Peru. Geologically, the group is by no means an old one, its earliest known 
representative ( Hylceobatraclius ) occurring in the Wealden strata of Belgium; and 
these animals do not appear to have become abundant until the Tertiary epoch. 
Nearly all newts and salamanders appear to be inhabitants of water during at 
least some period of their existence; some frequenting muddy swamps, and others 
deep lakes or subterranean waters, while a few are found in mountain-tarns at 
elevations of several thousand feet above the sea. Without exception nocturnal in 
their habits, spending the day in slumber either concealed in hiding-places on land, 
or at the bottom of the water in their aquatic haunts, and venturing abroad only 
at evening or after heavy rain, they are all difficult of observation, and consequently 
much still remains to be learnt with regard to their mode of life. The terrestrial 
species generally frequent soft, shady, damp spots, but occasionally narrow valleys 
or forests where they conceal themselves under stones or fallen trunks of trees, or 
in holes in the earth. During their permanent or temporary sojourn in the water, 
the adults of those species unprovided with external gills are obliged to come 
periodically to the surface in order to breathe; and while in that element all are 
less completely nocturnal than when on land. Such species as are inhabitants of 
cold regions undergo a period of torpidity during the winter months; while in 
tropical regions others become quiescent when their haunts are dried up. They 
exhibit a wonderful tenacity of life; and when dried up in mud, or frozen in ice, 
will awaken at the first shower of rain, or when their icy bonds are dissolved by 
the sun’s rays. They have also the capacity of reproducing lost limbs, apparently 
any number of times. Although on land the majority of species are slow and 
sluggish in their movements, some salamanders from the south and west of Europe, 
belonging to the genera Salamandrina and Chioglossa, run with the celerity of 
lizards; while others, again, climb sloping or perpendicular faces of rock, like 
geckos. In the water all swim quickly, mainly by means of serpentine movements 
of the tail; although the water-newts are perhaps the most expert swimmers. All 
are carnivorous in their diet, feeding chiefly upon molluscs, worms, spiders, and 
insects. Their breeding-habits are peculiar in that there is usually no union 
between the two sexes; the females seizing the packets of spermatozoa deposited 
by the males, and conveying them to their own reproductive chambers. While 
some species lajr eggs, in other cases the eggs are hatched within the bodies of the 
